ZFS Detection and Sanoid Installation
======================================

When archsetup runs, it should detect if the system is on ZFS and install sanoid.

Detection:
- Check if root filesystem is ZFS: `findmnt -n -o FSTYPE /` returns "zfs"
- Or check if zpool exists: `zpool list -H 2>/dev/null`

If ZFS detected:
1. Install sanoid from AUR: `yay -S sanoid`
2. Create /etc/sanoid/sanoid.conf (see below)
3. Enable the timer: `systemctl enable --now sanoid.timer`
4. Create the syncoid replication script and systemd units (see below)

Context:
- install-archzfs can't install sanoid (AUR package)
- archsetup already has AUR helper setup, so it's the right place to install it
- syncoid (for TrueNAS replication) comes with the sanoid package

Added: 2026-01-17

================================================================================
SANOID CONFIGURATION (/etc/sanoid/sanoid.conf)
================================================================================

# Sanoid configuration for ZFS snapshots
# Less aggressive - TrueNAS handles long-term backups

#############################
# Templates
#############################

[template_production]
    # Local rollback capability
    hourly = 6
    daily = 7
    weekly = 2
    monthly = 1
    autosnap = yes
    autoprune = yes

[template_backup]
    # Less frequent for large/static data
    hourly = 0
    daily = 3
    weekly = 2
    monthly = 1
    autosnap = yes
    autoprune = yes

[template_none]
    autosnap = no
    autoprune = yes

#############################
# Datasets
#############################

[zroot/ROOT/default]
    use_template = production

[zroot/home]
    use_template = production
    recursive = yes

[zroot/media]
    use_template = backup

[zroot/vms]
    use_template = backup

[zroot/var/log]
    use_template = production

[zroot/var/lib/pacman]
    use_template = production

[zroot/var/cache]
    use_template = none

[zroot/var/tmp]
    use_template = none

[zroot/tmp]
    use_template = none

================================================================================
SYNCOID REPLICATION SCRIPT (/usr/local/bin/zfs-replicate)
================================================================================

#!/bin/bash
# zfs-replicate - Replicate ZFS datasets to TrueNAS
#
# Usage:
#   zfs-replicate              # Replicate all configured datasets
#   zfs-replicate [dataset]    # Replicate specific dataset

set -e

# TrueNAS Configuration
# Try local network first, fall back to tailscale
TRUENAS_LOCAL="truenas.local"
TRUENAS_TAILSCALE="truenas"
TRUENAS_USER="root"
TRUENAS_POOL="vault"
BACKUP_PATH="backups"  # TODO: Configure actual path

# Datasets to replicate
DATASETS="zroot/ROOT/default zroot/home zroot/media zroot/vms"

# Colors
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
RED='\033[0;31m'
NC='\033[0m'

info()  { echo -e "${GREEN}[INFO]${NC} $1"; }
warn()  { echo -e "${YELLOW}[WARN]${NC} $1"; }
error() { echo -e "${RED}[ERROR]${NC} $1"; exit 1; }

command -v syncoid >/dev/null 2>&1 || error "syncoid not found. Install sanoid package."

# Determine which host to use
determine_host() {
    if ping -c 1 -W 2 "$TRUENAS_LOCAL" &>/dev/null; then
        echo "$TRUENAS_LOCAL"
    elif ping -c 1 -W 2 "$TRUENAS_TAILSCALE" &>/dev/null; then
        echo "$TRUENAS_TAILSCALE"
    else
        error "Cannot reach TrueNAS at $TRUENAS_LOCAL or $TRUENAS_TAILSCALE"
    fi
}

TRUENAS_HOST=$(determine_host)
info "Using TrueNAS host: $TRUENAS_HOST"

# Single dataset mode
if [[ -n "$1" ]]; then
    dataset="$1"
    dest="$TRUENAS_USER@$TRUENAS_HOST:$TRUENAS_POOL/$BACKUP_PATH/${dataset#zroot/}"
    info "Replicating $dataset -> $dest"
    syncoid --recursive "$dataset" "$dest"
    exit 0
fi

# Full replication
info "Starting ZFS replication to $TRUENAS_HOST"
echo ""

for dataset in $DATASETS; do
    dest="$TRUENAS_USER@$TRUENAS_HOST:$TRUENAS_POOL/$BACKUP_PATH/${dataset#zroot/}"
    info "Replicating $dataset -> $dest"

    if syncoid --recursive "$dataset" "$dest"; then
        info "  Success"
    else
        warn "  Failed (will retry next run)"
    fi
    echo ""
done

info "Replication complete."

================================================================================
SYSTEMD SERVICE (/etc/systemd/system/zfs-replicate.service)
================================================================================

[Unit]
Description=ZFS Replication to TrueNAS
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/zfs-replicate
User=root

[Install]
WantedBy=multi-user.target

================================================================================
SYSTEMD TIMER (/etc/systemd/system/zfs-replicate.timer)
================================================================================

[Unit]
Description=Run ZFS replication nightly

[Timer]
OnCalendar=*-*-* 02:00:00
RandomizedDelaySec=1800
Persistent=true

[Install]
WantedBy=timers.target

================================================================================
ENABLE REPLICATION
================================================================================

After SSH key auth is set up to TrueNAS:
  systemctl enable --now zfs-replicate.timer